The present invention relates to peristaltic pumps and in particular to a method and device for testing proper placement of a tubing in pumping engagement prior to operation of the peristaltic pump.
In peristaltic infusion pumps, and in particular linear peristaltic infusion pumps, appropriate placement of a tubing upon which the pumping mechanism of the pump has in the past been a manual function accomplished by the pump operator. Accurate alignment and proper installation of the tubing has been a function of operator skill and care. Because the tubing is flexible it has been possible to insert the tubing improperly close the door or other tubing capture or holding mechanism and activate the pumping mechanism with the improperly installed or misaligned tubing. Although efforts are made to always properly insert the tubing and also to use only a proper size and pump compatible wall thickness tubing, poor alignment or installation of an improper tubing can result in a malfunction or inaccurately metered fluid flow.
A tubing installation checking device and a method is provided in a peristaltic pump having a tube receiving channel and a door for holding a tubing therein. The checking device and method are for determining proper installation of a tubing along a receiving channel canal in to which the tubing is inserted for pumping engagement with a pumping mechanism. The checking device comprises a pressure sensor held in the peristaltic pump so that the pressure sensor is positioned along the tube receiving channel downstream from the pumping mechanism for sensing pressure in the tubing and for providing a signal representing the sensed pressure. A valve is also held in the peristaltic pump along said receiving channel downstream from said pressure sensor for closing a properly installed tubing in the tube receiving channel. The method is effectively implemented by a computer program operatively coupled to the peristaltic pump for activating the valve to close off fluid flow through the tubing after the tubing is installed and the door is shut, for activating the pumping mechanism for a partial pumping stroke, for receiving a first pressure signal from said pressure sensor indicative of the sensed pressure after the partial pumping stroke, for holding the pumping mechanism stationary a predetermined period of time, and for receiving a second pressure signal indicative of the pressure in the tubing after the predetermined time period, and for comparing the first and second pressure signals to determine whether there is fluid flow leakage through the tubing. If there is leakage through the tubing, such leakage is an indication of improper tubing installation and the program activates an alarm signal to indicate such improper tubing installation.
In an enhanced version an initial pressure is sensed in the tubing as soon as the tubing is inserted, the door is shut and the downstream valve is activated to close the tube. Then the pumping mechanism is activated for a partial pumping stroke and the first pressure is measured. The initialization pressure is compared to the first pressure to see whether the first pressure is higher as expected for a properly installed tubing. If not an initial alarm signal is provided and the remainder of the testing need not be implemented. If the first pressure is higher than the initialization pressure, then the second pressure is sensed after the predetermined period. The second pressure is compared to the first pressure to determine whether there is any drop in the pressure to indicate leaking through the tubing.
The present invention provides a method and a device for testing the proper loading of tubing into a peristaltic pump. The apparatus comprises a peristaltic pump having a tubing channel and a closeable door by which a tubing is engaged in the tubing channel of the pump. A pressure sensor is positioned adjacent to the tubing downstream from the pumping fingers, and a shutoff valve is positioned for engagement against and closure of the tubing downstream from the downstream sensor. Upon engagement of the tubing and prior to pump operation, the downstream valve closes the tubing, and the pumping fingers are engaged against the tubing and moved forward, creating a trapped pocket of fluid in the tubing downstream from the pumping fingers and upstream from the closed valve. The forward movement of the pumping fingers is stopped temporarily, and the pressure of the fluid trapped in the tubing is monitored by the downstream sensor. If the pressure signal initially increases upon movement of the pumping fingers forward and then remains constant when the movement of the pumping fingers is stopped, a good seal, and therefore proper alignment of the tubing in the pumping channel, is indicated. If the sensed pressure either does not increase when the pumping fingers are moved forward or increases and then rapidly decreases, there is an indication that either the closure valve has not closed the tubing fully or the pumping fingers do not completely collapse the tubing such that a leak is detected, indicative of misalignment or improper installation of the tubing into the peristaltic pump.